Conventionally, electric contact units having moveable contact members projecting from both sides of an insulating base board have been proposed for use as contact probe units for electrically testing electroconductive patterns of printed circuit boards and electronic component parts, sockets for semiconductor devices and electric connectors. In a typical contact probe unit employing such moveable contact members, a compression coil spring is coaxially received in each of a plurality of holders to urge a pair of contact needle members away from each other at the two opposite axial ends of the holder. The associated ends of the contact needle members and the compression coil spring are typically connected one another by soldering. Thus, an electric signal received by one of the contact needle members is transmitted to the other contact needle member via the compression coil spring.
However, when the electric signal passed through the contact probe unit is in high frequency ranges (for instance from 10 MHz to several GHz), some ill effects may be produced because the electric current is conducted by the coil-shaped electroconductive member. More specifically, when a high frequency signal is conducted through a coil-shaped electroconductive member, an inductive load is produced. Also, the resulting extended electroconductive path produces a resistive load to the detected signal.
In view of such problems of the prior art, the primary object of the present invention is to provide an electric contact unit which is low in both inductance and resistance.